Thermodynamics of CO2 reaction with methylamine in aqueous solution: A computational study

Subject Areas : Journal of Physical & Theoretical Chemistry

M. Hajmalek ¹ , K. Zare ² , H. Aghaie ³

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Received: 2014-04-25 Accepted : 2014-04-25 Published : 2013-07-01

Keywords: CO2 absorption, Amines, Density functional theory, Solvation model,

Abstract :

Separation and capture of carbon dioxide from the flue gas of power plants in order to reduceenvironmental damages has always been of interest to researchers. In this study, aqueous solution ofmethylamine was used as an absorbent for CO2 capture. In order to study this reaction, DensityFunctional Theory (DFT) was employed at the level of B3LYP/6-311++G(d,p) by using theconductor-like polarizable continuum model (CPCM). Two possible reaction products were studied:carbamate ion and bicarbonate ion. The estimation of the thermodynamic parameters indicated thatthe reaction of bicarbonate ion forming is not thermodynamically feasible at room temperature.However, the reaction of carbamate ion formation is exothermic (ΔH= -12.4 kcal mol-1) andexergonic (ΔG= -1.48 kcal mol-1). Also, various atomic radii were employed to build up the solutecavity within CPCM model and the effects of the solute cavity on the thermodynamic properties ofthe reaction were studied.